This application is directed to the upgrading of heavy crude oils. More particularly, this application is directed to a process of rendering such crudes suitable as feed for conventional refinery processes comprising oxidation of the heavy crude followed by mild coking and in situ deasphalting which produces high levels of demetalation with low solids rejection.
Oxidation/deasphalting and mild coking/in-situ deasphalting are processes individually known to be suitable for demetalizing heavy crude oils.
U.S. Pat. No. 4,379,747 discloses demetalation/deasphalting in coal liquefaction processes.
U.S. Pat. No. 4,358,361 and U.S. Pat. No. 4,089,771 disclose processes wherein residual oil fractions are coked following conventional demetalation processes.
However, in the instant process, the combination of oxidation/mild coking/in-situ deasphalting is novel offering several advantages. For example, it is a continuous process that gives higher levels of demetalation than mild coking/in-situ deasphalting while producing less rejected material than oxidation/deasphalting. This is of particular significance since heavy crudes will be a more abundant source of fuel in the future because light crude supplies are decreasing. Therefore, demetalation and upgrading of heavy crudes prior to downstream processing will become more and more a necessity if such materials are to be used in conventional refinery systems.